Re: [gentoo-dev] Revision bumps vs git commits atomicity

[Daniel Campbell]

On 12/02/2016 07:14 AM, Andrew Savchenko wrote:
> Hi all!
>
> Right now we have two somewhat conflicting policies (at least up to
> my understanding of them):
>
> 1) git atomic commits [1]:
> each logical change should be a separate commit.
>
> 2) revision bump policy [2]:
> each change sufficiently affecting application run-time or
> installed files should have a revision bump.
>
> Let's consider the following quite common scenario: package foo-1.0
> should be updated to foo-1.1, but aside from version bump there is
> a set of accumulated issues which maintainer is willing to handle,
> e.g.:
> - bump to EAPI 6;
> - fix several runtime bugs (still present in the new version);
> - install missing documentation;
> - add previously omitted USE flags for some tools of controllable
> functionalities;
> - etc...
>
> If both policies are to be followed, users will see something like:
> foo-1.0 -> foo-1.1-r8 (assuming each sufficient change was made as
> a separate commit with a revision bump).
>
> While such versioning change is technically correct, it is
> confusing for our users and makes future maintainance harder,
> because of multiple file renames (yeah, I know about git diff
> --find-renames, but this kludge is not perfect).
>
> What about the following forkflow:
> - version bump first with minimal changes required, but without
> pushing commit to the tree;
> - make each logical change as a separate commit without revision
> bumps and without pushing stuff to the tree (of course repoman
> scan/full is required as usual for each commit);
> - well test package after the last commit (that it builds with
> various USE flag combinations, old and new functionality works fine
> and so on);
> - fix any problems found and only afterwards push changes to the
> tree.
>
> This way users will see only foo-1.0 -> foo-1.1 change in the tree,
> while git will still retain each logical change as a separate
> commit, which will make future maintenance and debugging much
> easier.
>
> Of course a separate git branch may be used as well, but using
> branches for each half-a-dozen set of commits looks like an
> overkill to me.
>
> Thoughts, comments?
>
> [1] https://devmanual.gentoo.org/ebuild-maintenance/index.html
> [2] https://devmanual.gentoo.org/general-concepts/ebuild-revisions/index.html
>
> Best regards,
> Andrew Savchenko
>
I've always worked as if each commit needed to be working for Gentoo
users. So if I need to version bump, that's a separate commit. However,
let's say I found a bug in the ebuild itself for foo-1.0. The way I see
it is I should bump to foo-1.0-r1 to fix the bug in that ebuild, _then_
version bump so that foo-1.1 already has the fixes that foo-1.0-r1 has.
If I version bump first, then I have to revbump both and that just
increases my odds of forgetting to put the fixes into all the correct
ebuilds.

It results in the appropriate fixes in the older package, and the new
version comes with the old one's fixes (plus any changes the new ebuild
might need due to upstream changes).

Does that make any sense?

-- 
Daniel Campbell - Gentoo Developer
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